NET
7 For the lips of a priest should preserve knowledge of sacred things, and people should seek instruction from him because he is the messenger of the Lord of Heaven’s Armies.
Darby
7 For the priest's lips should keep knowledge, and at his mouth they seek the law; for he is the messenger of Jehovah of hosts.
KJV
7 For the priest's lips should keep knowledge, and they should seek the law at his mouth: for he [is] the messenger of the LORD of hosts.